How can I transfer custom code between themes?

[orange1989]

Hello, experts!

I previously hired a developer to custom-code a minimum order quantity on some of my products. Now, I'm changing my theme and designed the website myself but not knowledgeable enough about liquid. 

Can someone teach me how I can paste the codes from one theme to another?

[PaulNewton]

Not all themes are built on the same foundations.

Sometimes a minimum amount can be as simple as finding the relevant product-form snippet or section and finding the quantity input and giving it a min attribute and value.

https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/number#min 

But that is purely based on a static value for all products-variants, a theme not using javascript  or other features that may ignore or not render that qty input, etc.

Often there should be some related setting that reads what should be the value of the minimum such as in a metafield, or logic based on a tag etc.

If you need it looked at and the feature documented for any other future migrations then you can contact me. Contact info in signature please include context: post urls, store url, theme name, problem detail, etc.